How does blood travel around the body?
Arteries
Veins
Capillaries
Describe the functions of the heart in the pumping of blood
- the right side of the heart pumping blood to the lungs
- the left side of the heart pumping blood to the rest of the body
Where is blood under high pressure?
In the arteries which is under higher pressure than blood in the veins
Explain in terms of pressure difference why blood flows from one area to another?
It is this pressure difference that causes blood to flow around the body
Explain the advantage of the double circulatory system in mammals
Higher pressures
Therefore greater rate of flow to the tissues
Explain how the adaptations of arteries, veins and capillaries relate to their functions
- Thick muscular and elastic wall in arteries to cope with high pressure
- Large lumen and presence of valves in veins to prevent the back flow of blood
- Permeability of capillaries to allow the exchange of substances between cells and blood
Explain how the structure of a red blood cell is adapted to its function in terms of the small size providing a large surface area to volume ratio
- small and flexible so they can pass through narrow blood vessels
- shape of the cells increases their surface area for transferring oxygen
Describe how haemoglobin in red blood cells reacts with oxygen in the lungs to form oxyhemoglobin and how the reverse of this reaction happens in the tissues
When the cells reach the lungs, oxygen diffuses from the lungs into the blood. The haemoglobin molecules in the red blood cells bind with the oxygen to form oxyhemoglobin.
Haemoglobin + oxygen ⇌ oxyhemoglobin
Explain why the left ventricle has a thicker muscle wall than the right ventricle
Because it has to pump blood around the whole body
Describe the function of plasma
Transports:
- carbon dioxide from the cells to the lungs
- glucose and other digested food products from the small intestine to the cells
- waste products from the liver to the kidneys
- hormones to the target organs
- antibodies around the body to fight disease
Describe how the parts of the circulatory system work together to bring about the transport of the substances around the body
- arteries transporting blood away from the hesrt
- veins transporting blood to the heart
- capillaries exchanging materials with tissues
Identify the names and positions of the parts of the heart and functions
- left and right ventricles to pump blood
- left and right atria to receive blood
- semilunar , tricuspid and bicuspid valves to prevent back flow
- four main blood vessels of the heart
Describe the functions of components of the blood:
Red blood cells
White blood cells
Platelets
Red blood cells - transport oxygen from the lungs to the tissues
White blood cells - protect the body against disease
Platelets - clump together when a blood vessel becomes damages and form a meshwork of fibres to produce a clot
